Tuyere block



Feb. 7, 1933. J. w. ARMOUR 1,396,569

TUYERE BLOCK Filed Dec. 10, 1930 2 Shets-Sheet 1 INVENTOR IQ IES W ARMOUR ATTORNEY I Feb. 7, 1933. J. w. ARMOUR TUYERE BLOCK Filed Dec. 10, 1950 2 Sheets-Sheet 2 INVENTOR @5156 WI ARMOUR Qua: $14 M f ATTORNE I I Patented Feb. 7, 1 93 3 "UNITED STATES "PATENT F ICE "JAMES w. ARMOUR, or woR oEsTnR, MASSACHUSETTS, ASsIeNoa To RILEY s'roxun CORPORATION, or WORCESTER, MASSACHUSETTS, AooaroRATroN' or mssaonuits way downwardly through the openings in .SETT

' TU YERE Brook;

Application filed December 10, 1930. Serial No. 501,253.

' This invention relates to tuyere blocks, and more particularly to tuyere blocks for automatic stokers of the underfeed type.

y In underfeed stokers the fuel is usually de- 5 livered through openings in the front wall of afurnace into troughs or retorts provided with air admittingtuyere blocks along their upper margins} Air under pressure flows from an air chamber beneath the retorts through openings in the tuyere blocks into the fuel bed. The retorts usually slope downwardly toward an ash dump at the rear of the furnace, where the incombustible residues from the fuel are deposited. Such a Stoker usually provides a flame which tends to concentrate at therearportion of the furnace because of the downwardly and rearwardly sloping fuel bed and as a result the front part of the furnace combustion s space is not'utilized efficiently; -Moreover in operating a stoker of this type, it is-found that the fuel bed will sometimes become too thin in a small localized area. This reduces the resistance to the flow of air through the adjacent'tuyere blocks, and the velocity of flow increases considerably; As a result the high velocity air jets pick up small particles of unburned fuel and deposit them inthe ash dump where they become mixed with the ashes without 'further'opportunity to be consumed. This combustion.

1 It is accordingly one oblj ect of my invention P to overcomethese'difiicu ties and to prov1de J a tuyere block for an underfeed stoker which will tend to distribute the flame uniformly throughout the furnaceand which will function properly even in areas where the fuel bed is abnormally thin, and have but little 0 tendency to blow unconsumed fuel rearwardly onto the ash dump. I

A part of the fuel which is delivered to the furnace ofan underfeed stoker usually finds the tuyereblocks and into the air chamber between. This fuel is known as siftings,

and causes great inconvenience. It must be .tuyere blocks ship;

greatly reducesthe efliciency of -tu yere blocks.

tu'yere blocks are reciprocated, as in certain types of underfeed stokers, there is a tendency to increase the amount of siftings', since the blocks during their rearward movement are thrust directly into the mass of fuel. i

It is accordingly a further object of the present invention to provide an under-feed tuyere block which will reduce the siftting of fine fuel to a minim Particularly when used on stokers which are arranged to reciprocate the tuyere blocks.

It is a further object of my invention to provide a tuyre block which can be manufactured economically, and'which will deliver air to the fuel bed efliciently throughout,

along life of usefulness before requiring replacement. p V p With these and other objects in view, as will be apparent'to those skilled in the art, my

the claims appended hereto. 7 r g r In accordance with my invention I provide ai-tuyere block arranged to be mounted on "l0 nvention resides in the comb nation of parts set forth in the specification and covered by 'erably comprisesa body portion, which may be a flat substantially horizontal plate or web adapted for mounting in step-like formation with other similar blocks. This plate may be provided with airjdirecting ribs. The side :of the block preferably slopes away from the retort in a direction toward the rear of the furnace, particularly when it is to be used on a stoker of the type utilizing reciprocating Referring to the drawings illustrating one embodiment of my invention and in which like reference numerals indicate like parts.

Fig. 1 is a side view of'a stoker applied to a furnace, the parts within the furnace being shown in sectionon. thelline 1-l of Fig. 2;

Fig; 2 is a slightly enlarged section of a portion of the stoker on the line 2' 2 of Fig. 1;

Fig.3 is an enlarged top plan view of eight grouped in assembled relation- Fig. 4 is a side ielevation of the bloclis for the fuel bed and deliver ai shown in Fig. 3, partially broken away for clearness of illustration;

Fig. 5 is a bottom plan View of four of the blocks shown in Fig. 3;

Fig. 6 is a perspective view of a tuyere block, looking at the top thereof; and

Fig. 7 is a perspective view of a tuyere block, looking at the bottom thereof.

In the drawings I have illustrated my vention as applied to an underfeed stoker of the'multiple retort type. This comprises a fuel hopper 10 of suitable construction which is mounted outside of and adjacent to the vertical front wall. 11 of afurnare. A plurality of horizontal cylindrical ram casings 12 are mounted beneath the hopper and arranged to receive fuel therefrom. A suitable ram, not illustrated, is arranged to be reciprocated within eachram casing by a rotatable crank shaft 14, as is well known in this art. This crank shaft is arranged to be rotated at aslow speed by a suitable gear reduction device 16 which may be driven by any desired source of power. The weight of the casings and associated parts may be supported on pipe columns 17 which rest on a. concrete floor 18.

A plurality of parallel underfeed retorts 20 extend rearwardly from the front wall 11. These retorts are provided with stationary bottom plates 21 which incline downwardly at a'slight angle toward the rear of the furnace. The sides of the retorts are formed by hollow side bars 2 which are arranged to support on their upper surfaces the tuyere blocks 25. These tuyere blocks are arranged in rows extending longitudinally of the stoker between the retorts and they form a support thereto.

In the embodiment illustrated I have shown these side bars as being suitably constructed for horizontal reciprocation. For this purpose each side bar is supported at its forward end on a cylindrical member 26 which is mounted in a slide bearing 28 forming an integral part of the ram casing. Each side bar is arranged to be reciprocated by its corresponding ram through a lost motion connection 30 in a manner well known in this art and fully disclosed in the patent to Riley No. 1.090 651. At its lower and rearward end each side bar attached to a shoe 32 arranged to slide over the upper plane surface of a base plate 33 which is bolted to a pair of Lbeams 35. These I-beams extend transversely of the stoker and rest in suitable pockets in the side walls of the furnace as will be well understood.

The stoker as illustrated is provided with an overfeed grate section 36. This may be of any suitable construction and is mounted on the side bars 24: beneath the lower end of the retort 20. This ovcrfeed grate serves as a tuyere structure to furnish air for the combustion of any unconsumed coke which issues from the lower end of the underfeed retort.

In the rear of the ovcrfeed grate 36 I have illustrated a rocker dump plate 33, the upper and forward end of which is pivotally connected to the shoe 32. The rocker plates rest at their lower ends on rolls 40 suitably mounted at the rear ends of horizontal rack bars 41. A vertical bridge wall 4-3 is arranged in the rear of tne rocker plates and in substantial proximity thereto. The position of the rocker plates 38 in relation to the bridge wall may be adjusted by means of a horizontal shaft mounted in suitable brackets 46 which are bolted to the forward I-beam This shaft carries a series of pinions 4-8 which mesh with the teeth on the rack bars. It will be understood that the shaft 45 extends through the sidewalls of the furnace and is arranged to be controlled from a convenient point.

A vertical plate 50 is mounted beneath the front wall 11 of the furnace so as to entirely enclose a space beneath the stoker retorts and form a pressure chamber 52. Air may be sup plied to this pressure chamber from any suitable forced draft apparatus, such as a fan, through a duct 53 which may be provided with damper 541. Air flows under pressure from the air chamber 52 up through the hollow sidebars 24. to the tuyere blocks 25 which deliver it to the fuel bed for combustion.

The present invention is concerned with the construction and arrangement of the tuyere blocks 25. In the preferred embodiment illustrated. each tuyere block comprises a thin elongated flat substantially horizontal plate or web 56 arranged to be mounted in a step-like formation with other similar blocks, as shown particularly in Fig. l. lVith this arrangement the major part of each block is covered by the block above. and only the rear or nose portion 57 of the block is exposed on its upper surface to the heat of the fuel bed.

The blocks 25 are arranged to deliver air to the fuel bed for combustion, and they are so shaped as to direct this air in jets at an angle toward the front of the furnace in order to prevent the blowing of fine fuel on to the ash dump. For this purpose I have shown a number of spaced parallel ribs 58 on one face of the web which form air channels terminating at the retort side of the block. In the embodiment illustrated these are located on the lower face of the web T iese ribs extend inwardly for substantial distance from the outer edge 60 of the web adjacent to the retort, and they are inclined at an angle toward the front of the furnace. as shown particularly in Figs. 5 and. 7. The ribs 58 thus direct jets of air in directions opposed to the rearward movement of the fuel and into the mass of fuel in the reto-rts 20. The outer edge 60 of the block is shaped to slope away from the retort toward the rear of the furnace thus reducing the tendency of the rearwardly moving fuel to enter the air openings. With this construction, the front end may be arranged to direct air rearwardly as.

shown. When, as in the embodiment illustrated, the tuyere blocks are to be used on a stoker of the well known Riley type, each block is formed with a straight side edge 63 which at assembly is located parallel to the center line 7 f the retort and in contact with the corresponding portion of the laterally adjacent block, as shown in Fig. 3. As there illustrated, the blocks of adjacent rows are made of opposite hand. In orderto prevent air leakage at the joint between tuyere rows,I

provide a depending rib 64 extending length-] wise along the edge 63 of each block. This forms an effective seal. A rectangular opening 65 is preferably providedin the forward portion of the web to reduce the resistance to the flow of air through the blocks.

It is desirable that the air jets from the tuyere blocks should issue into'the fuel bed at points located materially abovethe upper" margins of the side bars 24. With this arrangement the hot combustion zone is spaced sufliciently from the side bars to avoid danger of burning them. For this purpose, I preferably provide depending vertical plate or flange portions 67 which extend downwardly at each side of the block near the front end thereof and provide an air passageleading to the channels between the ribs 58. The lower edges of these flanges 67 are formed at an angle corresponding to the slope of the side bars 24 on which they rest. The front corners of the blocks are preferably cut out at 68 to form overlapping joints between adjacent blocks, as shown in Fig. 5. This reducesthe opportunity forair leakage. The front edges of the flanges 67 are connected by a strengthening plate 69. I

I prefertobolt the 'tuyere blocks 25 in place on the side bars 24, and for this purpose I provide the web. 56 of each block with a bolt hole 71 through which a bolt 72 (Fig. 2) may extend. A shallow square recess 7 3 isshown in the upper surface of the web to receive the head of the bolt Aslightly raised boss'74 may be provided on the lower surface of the Web for strengthening purposes To assist in holding the blocks in proper alignment,

I may utilize a lug 75 extending upwardly from each block and in position to contact laterally with the rib 64 on the block above.

The operation of my invention will now be apparent from the above disclosure. Air

under pressure from the chamber 52 passesupwardly'through the side bars 24 to the tuyere blocks 25and into the fuel bed through channels between the ribs 58. A small {Partpfthfair flows between the ribs 61 and i thuscools the nose portions 57 ofthe blocks.

:The greater part of the" air for combustion iisidirected towardthe front of thefurnace :byi'thearibsfi8. This construction avoids the blowing of fine coal into the ash dump and tends to: distribute the flame more uniformly -i-'n; the furna'ce.chamber. The forwardly di- %rected:air.jetsalso penetrate the mass of fuel ;in .the retorts,more effectively. The side bars and tuyereblocks are reciprocated to feed the fuel and ash towards the dump plates 38. 'Duringtherearward movement of the tuyre blocks, entry of fine fuel into the channels betweenthe" ribs 58 is prevented by the angu- -.lararrangementof the These ribs act like plows which crowdzthe coal away. Dur- E'ing. the: forward movement ofnthe tuyere' b'locksthe a'ir feeding edges 60 of the blocks 'imove' away from the packed fuel as a result for. their slopingconstruction. This relieves- .the pressure and there is but little opportuni- IC ai'nber.v v :xHaving thus-described my invention what I; claim as new and desire to secure byLetters ty forfine fuel tosift through into the air '5 Patent is! j +11. 'Ani. underfeed stokerfcomprisingside a walls defininga retort. through which fuel isv moved in a direction. lengthwise thereof, and

1a; "series :of long I..substantially horizontal tuyererblocksfmounted onthe upper margins ofithe walls and arranged in step-like formation, each-= tu-yere blockhavingan edge exposed to the fuel and sloping away from the more in the direction of; fuel movement, and a series of spacedribs formingair channels terminating at said edge which direct air at anrangle'iopposed to the direction of fuel movement. i l' W 1' 1 2. Anu'nderfeed stoker comprising relatively" reciprocable sidebars forming the wallsof adj acent'retorts, and a series of long substantially horizontal tuyere blocks mounted on'each barinstep-like formation, the :adj acent' faces of the blocks in'thc' two series being in contact and parallel with the center line 10f the retort, and the opposite faces of the. blocks being exposed towards the retort and sloping away from said center line,each .tuyere iblock having a seriesof spaced ribs forming channels communicating with the spacebeneath the blocks and between the side bars which terni inate'at the exposed faces and slope in a direction ment.

3. tuyere block for a multiple retort underfeed stoker comprising an; elongated flat substantially horizontal web having one of its longedges sloping, whereby one end of the web is widerthan the other, and a series of spaced ribs on the web which provide air flow channels terminating at the sloping opposed to the fuel moveedge and arranged at an angle extending 'outwardly and toward the wider end of the web.

4. A tuyere block for a multiple retort underfeed stoker comprising an elongated fiat substantially horizontal web having one of its long edges sloping, whereby one end of the web is wider than the other, a series of spaced ribs on the web which provide air flow channels terminating at the sloping edge and arranged at an angle extending outwardly and toward the wider end of the web, and depending flanges at the wider end of the web which provide an air passage leading to said channels. I

5. A tuyere block for an' underfeed stoker comprising an elongated flat substantially horizontal web so constructed that it may be piled in step-like formationwith the webs of other similar blocks, whereby one end of the web will be exposed, and a series of spaced ribs on the web which provide air flow channels terminating at one of the long edges of theweb-and arranged at an angle extending outwardly and away from the exposed end of the web. I

6. A tuyere structure for an underfeed stoker comprising a series oftuyere blocks arranged in a step-like formation sloping downwardly and rea rwardly, each block having means thereon for directing air in jets at an angle laterally and forwardly.

7. An underfeed stokercomprising side Walls defining a retort through whichfuel is moved in a substantially horizontal direction lengthwise of the retort, and a series of tuyere blocks mounted on the'upper margins of the walls, the blocks being shaped to provide air passages which direct air into the retort at an angle opposed to the direction of fuel movement.

8. An underfeed stoker comprising side walls defining a retort through which fuel is moved in a direction lengthwise thereof, and a series of long substantially horizontal tuyere blocks mounted on the upper margins of the walls and arranged in step-like formation, each tuyere block having an edge exposed to the fuel in the retort, and a series of spaced ribs forming air channels terminating at said edge which direct air at an angle opposed to the direction of fuel movement.

Si ned at Worcester, Massachusetts, this 8th day of December, 1930. I

JAMES W. ARMOUR. 

